#include<iostream>
#include<vector>
#include<unordered_map>
#include<cstdint>
#include<functional>
#include<memory>
#include<unistd.h>

using TaskFunc = std::function<void()>;
using ReleaseFunc = std::function<void()>;
class TimerTask
{
    private:
        uint64_t _id;  //定时器任务对象ID
        uint32_t _timeout; //定时任务的超时时间
        bool _canceled;  //false-表示没有被取消，true-表示被取消
        TaskFunc _task_cb; //定时器对象要执行的定时任务
        ReleaseFunc _release; //用于删除TimerWheel中保存的定时器对象信息
    public:
        TimerTask(uint64_t id,uint32_t delay,const TaskFunc &cb):_id(id),_timeout(delay),_task_cb(cb),_canceled(false){}
        ~TimerTask()
        {
            if(_canceled == false)
                _task_cb(); 
            _release(); 
        }
        void Cancel()
        {
            _canceled = true;
        }
        void SetRelease(const ReleaseFunc &cb){ _release = cb; }
        uint32_t Delaytime(){ return _timeout; }
};

class TimerWheel
{
    private:
        using WeakTask = std::weak_ptr<TimerTask>;
        using PtrTask = std::shared_ptr<TimerTask>;
        int _tick; //当前的秒针，走到哪里释放哪里，就相当于执行哪里的任务
        int _capacity;  //表盘的最大数量--其实就是最大延迟时间
        std::vector<std::vector<PtrTask>> _wheel;
        std::unordered_map<uint64_t,WeakTask> _timers;
    private:
        void RemoveTimer(uint64_t id)
        {
            auto it = _timers.find(id);
            if(it != _timers.end())
            {
                _timers.erase(it);
            }
        }
    public:
        TimerWheel():_capacity(60),_tick(0),_wheel(_capacity){}
        void TimerAdd(uint64_t id,uint32_t delay,const TaskFunc &cb)
        {
            PtrTask pt(new TimerTask(id,delay,cb));
            pt->SetRelease(std::bind(&TimerWheel::RemoveTimer,this,id));
            int pos = (_tick + delay) % _capacity;
            _wheel[pos].push_back(pt);
            _timers[id] = WeakTask(pt);
        }
        //刷新/延迟定时任务
        void TimerRefresh(uint64_t id)
        {
            //通过保存的定时器对象的weak_ptr构造一个shared_ptr出来，添加到轮子中
            auto it = _timers.find(id);
            if(it == _timers.end())
            {
                return;//没找到定时任务，没法刷新，没法延迟
            }
            PtrTask pt = it->second.lock();//lock获取weak_ptr管理的对象对应的shared_ptr
            int delay = pt->Delaytime();
            int pos = (_tick + delay)% _capacity;
            _wheel[pos].push_back(pt);
        }
        void TimerCancel(uint64_t id)
        {
            auto it = _timers.find(id);
            if(it == _timers.end())
            {
                return;//没找到定时任务
            }
            PtrTask pt = it->second.lock();
            if(pt) pt->Cancel();
        }
        //这个函数应该每秒钟被执行一次，相当于秒针向后走了一步
        void RunTimerTask()
        {
            _tick = (_tick + 1) % _capacity;
            _wheel[_tick].clear();//清空指定位置的数组，就会把数组中保存的所有管理定时器对象的shared_ptr释放掉
        }
};

class Test
{
    public:
        Test(){std::cout << "构造" << std::endl; }
        ~Test(){std::cout << "析构" << std::endl; }
};

void DelTest(Test *t)
{
    delete t;
}

int main()
{
    TimerWheel tw;
    Test *t = new Test();
    tw.TimerAdd(888,5,std::bind(DelTest,t));
    for(int i = 0;i<5;i++)
    {
        sleep(1);
        tw.TimerRefresh(888);//刷新定时任务
        tw.RunTimerTask();//向后移动秒针
        std::cout<<"刷新了一下定时任务，重新需要5s后才会销毁\n";
    }
    tw.TimerCancel(888);
    while(1)
    {
        sleep(1);
        std::cout<<"-----------------------\n";
        tw.RunTimerTask();//向后移动秒针
    }
    return 0;
}